I need help! (area restrictions in obj movement ... and obj chg by line intersection)

Hi Everyone , i’m new here and i seriously want someone to help mie in my flash 8 applications…

I’m currently doing a flash app on ray diagrams under a converging lens.

As you see , i’m having some problems … which i’m unavailable to solve it for quite some time.

i will really appreciate if anyone will willing to open my fla file to take alook or gif me some suggestions/ideas to improve my design …thx

PS: i really a flash noob~ sobsob~